Numerous systems are known in the prior art for desalinating sea water. Many of the prior art systems utilize reverse osmosis to accomplish such objective. Typically, prior art desalinization systems are very expensive to operate and difficult to service. Piston pumps are known expedients for pressurizing sea water or other liquid to be separated into permeate portions and concentrate portions. Turbine pumps are another well known expedient for accomplishing that objective.
Inefficient in any event, such prior art arrangements become even more so unless optimum pressures are maintained in the system for particular conditions such as the temperature of the sea water. Prior art systems are generally such that pressure adjustment is difficult if not impossible, particularly on an efficient and economic basis. Pump or turbine input speeds must normally be regulated in the prior art systems and this is difficult to do when alternating current is the power source.
The following United States patents are known and are believed to be representative of the state of the prior art in this field: U.S. Pat. No. 4,973,408, issued Nov. 27, 1990, U.S. Pat. No. 4,836,924, issued Jun. 6, 1989, U.S. Pat. No. 4,995,795, issued Feb. 26, 1991, U.S. Pat. No. 5,193,988, issued Mar. 16, 1993, U.S. Pat. No. Re. 33,135, Dec. 26, 1989, U.S. Pat. No. 4,124,488, issued Nov. 7, 1978, U.S. Pat. No. 4,686,831, issued Aug. 18, 1987, U.S. Pat. No. 4,983,301, issued Jan. 8, 1991, U.S. Pat. No. 4,983,305, issued Jan. 8, 1991, U.S. Pat. No. 5,203,803, issued Apr. 20, 1993, U.S. Pat. No. 4,702,842, issued Oct. 27, 1987, U.S. Pat. No. 4,842,725, issued Jun. 27, 1989, U.S. Pat. No. 4,756,830, issued Jul. 12, 1988, and U.S. Pat. No. 4,966,708, issued Oct. 30, 1990.